THURSDAY, March 18, 2004 (HealthDayNews) -- A brain dysfunction in some people with cirrhosis may impair their driving ability to the point that they're unfit to drive, says a study in the March issue of Hepatology.
This cirrhosis-related brain dysfunction is called minimal hepatic encephalopathy (MHE), which causes problems in behavior, intelligence, consciousness and neuromuscular function. Previous research suggested that even low levels of cerebral dysfunction can impair a person's quality of life and make him unfit to drive.
In this study, Christian Wein of the University of Hamburg in Germany and his colleagues studied 48 people with cirrhosis and 49 people who did not have the liver disease. Fourteen of the people with cirrhosis had MHE.
All the people completed a standardized on-road driving test designed for people with brain injury. They were scored by a professional driving instructor who had no knowledge of each person's health status.
The total driving scores of the people with MHE were significantly worse than those of both the cirrhosis patients without MHE and the control subjects. The people with MHE performed worse in car handling, adaptation, cautiousness, following road signs and rules, attention to pedestrians and cyclists, checking the rearview mirror before changing lanes, tracking and signaling to turn.
The driving instructor had to intervene to avoid an accident during five of the 14 driving tests he conducted with MHE patients. That rate was nearly 10 times greater than in the other groups.
"In this study, patients with MHE showed a diminished ability to drive a car, as indicated by the assessment of a professional driving instructor who was not aware of the diagnoses of the patients and the psychometric test results. Thus, MHE, but not cirrhosis per se, seems to impair the fitness to drive," the study authors write.
The authors add that people with MHE need to be told about the risk that their driving ability may be impaired. While the authors endorse surveillance and treatment of people with MHE, they also say they can't conclude that all people with MHE are unfit to drive.
More information
The American Gastroenterological Association has more about cirrhosis.
